(1) Field of the Invention
The present invention relates to an oil filter mounting arrangement for a four-cycle, inline multi-cylinder motorcycle engine.
(2) Description of the Prior Art
In many motorcycles having a four-cycle multi-cylinder engine mounted thereon, an inline multi-cylinder engine unit having its multiple cylinders inclined forwards with its crankshaft extending widthwise of the bodywork is arranged and suspended in the lower front part of the motorcycle bodywork. In the exhaust system of such an engine, exhaust pipes connected to exhaust ports on the upper front side of the forward tilting cylinders extend from the front part of the engine unit downwards and further are bent around the bottom of the engine unit and directed to the rear so that they are connected together or individually to the muffler arranged in the rear part of the motorcycle body.
In a motorcycle of the above type, in order to minimize bulges to the left and right of the body, the oil filter of the engine unit is attached to the front part of the engine case. In particular, this oil filter arrangement is especially necessary for a motorcycle with its bodywork totally covered by a fairing.
Since the exhaust pipes are laid out in front of and under the oil filter, there occurs an inconvenience of the engine oil dripping and running over the exhaust pipes when the filter is replaced if no countermeasure is taken.
As a prior art oil filter layout configuration of an engine unit of this type, Japanese Patent Application Laid-Open Hei 10 No. 238327 is disclosed. With reference to FIG. 1 showing this prior art, of exhaust pipes 113 extending from the engine (power unit 140), two exhaust pipes 113 in the center are laid out to the left and right sides avoiding the center of the engine, viewed from the front to form a spacing between the exhaust pipes 113, where an oil filter 152 is attached to the engine case. That is, it is considered that the two exhaust pipes 113 in the center are arranged apart in order to avoid oil dropping since the inconvenience of oil dripping from oil filter 152 is attributed to the fact that exhaust pipes 113 are located below oil filter 152. In this figure, 146, 148 and 155 designate a head cover, AC generator and breather chamber, respectively.
The arrangement where the oil filter is arranged in the engine center while the exhaust pipes are laid out avoiding the space under the oil filter viewed from the front, however, makes the exhaust pipes spread and bulge to the left and right sides. As a result, the motorcycle is possible to touch the road surface even at a small bank angle when the bike is banked. Thus, this arrangement constrains and impedes tilting of the bike at a large bank angle.
Particularly for sport motorcycles, active riding performance is important, so that inability to assume a large bank angle means a low turning performance, a serious drawback.
There are cases where an oil cooler is provided along with the oil filter in order to improve the engine cooling performance. In such a case, if the oil filter and oil cooler are laid one over another with respect to the motorcycle""s front to rear direction, as disclosed in Japanese Patent Application Laid-Open Hei 7 No. 11955, these will not impede the exhaust pipes. However, if the capacity of the oil cooler is attempted to be increased, the oil cooler becomes large in diameter, hence unavoidably needing a large space between the exhaust pipes, again raising the bank angle concern. Alternatively, if the oil cooler is made too large with respect to the vehicle""s front to rear direction in order to secure its capacity, there is a possibility that the oil filter might interfere with the exhaust pipes upon replacement of the filter.
The present invention has been devised in view of the above drawbacks, and it is therefore an object of the present invention to provide an oil filter mounting arrangement for a four-cycle motorcycle engine, which prevents oil dripping from the oil filter from staining the exhaust pipes upon replacement of the oil filter and permits riding at a large bank angle while providing an oil cooler of a large capacity.
In order to achieve the above object, the present invention is configured as follows:
In accordance with the first aspect of the present invention, an oil filter mounting arrangement for a four-cycle engine for use in a motorcycle wherein the inline multi-cylinder engine comprises: a crankshaft laid out widthwise of the bodywork and mounted in the front lower part of the bodywork; a multiple number of exhaust pipes extended from the front upper part of the engine to the lower part of the engine and bent toward the rear; an oil pan having both side surfaces inclined; and a multiple number of exhaust pipes extended to the rear while being split to the left and right along the inclined side surfaces, forming a spacing between the exhaust pipes, is characterized in that an oil filter and oil cooler is projectively arranged forwards, side by side, in the lower front part of the engine; the oil filter is disposed on the side opposite to the kickstand with respect to the vehicle""s center line; and the spacing between the exhaust pipes is positioned vertically below the oil filter in the state where the kickstand is set grounded.
In accordance with the second aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above first feature is characterized in that when the kickstand is retracted in the unused state, one of the exhaust pipes is arranged vertically below the oil filter.
In accordance with the third aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above first feature is characterized in that the exhaust pipes are gathered below the engine while the oil filter is disposed in front of the gathering of the exhaust pipes.
In accordance with the fourth aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above second feature is characterized in that the exhaust pipes are gathered below the engine while the oil filter is disposed in front of the gathering of the exhaust pipes.
In accordance with the fifth aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above first feature is characterized in that the motorcycle bodywork including the engine sides is covered by a fairing.
In accordance with the sixth aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above second feature is characterized in that the motorcycle bodywork including the engine sides is covered by a fairing.
In accordance with the seventh aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above third feature is characterized in that the motorcycle bodywork including the engine sides is covered by a fairing.
In accordance with the eighth aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having the above fourth feature is characterized in that the motorcycle bodywork including the engine sides is covered by a fairing.
In accordance with the ninth aspect of the present invention, the oil filter mounting arrangement for a four-cycle engine for use in a motorcycle, having any of the above first through eighth features is characterized in that the oil cooler is disposed on the same side as the water pump is, with respect to the front to rear direction of the motorcycle.
According to the present invention, since the oil filter and oil cooler are arranged side by side and projected forwards, at the lower front part of the engine, it is possible to enlarge the oil filter and oil cooler in their radius direction and hence enlarge their capacities without having to take care of obstacles. Further, since the oil filter is arranged offset on the side opposite to the kickstand with respect to the vehicle""s center line while the spacing between the exhaust pipes are formed vertically below the oil filter when the kickstand is set down, the oil dropping during replacement of the oil filter will not stain the exhaust pipes.
In the present invention, one of the preferable features is that one of the exhaust pipes is arranged vertically below the oil filter when the kickstand is retracted in its unused position. With this arrangement, when the kickstand is set down(in the parking state), the spacing between the exhaust pipes can be positioned vertically below the oil filter. Since the spacing between the exhaust pipes is not located vertically below the oil filter when the motorcycle is set upright where the oil filter is not usually replaced, it is possible to inhibit the spread of the exhaust pipes to the left and right sides as low as possible. As a result, it is possible to assume a large bank angle. Since the oil filter and oil cooler are arranged side by side in the present invention, the position of the oil filter is offset from the center of the vehicle. If, in such a motorcycle, the spacing between the exhaust pipes is positioned vertically below the oil filter with the motorcycle positioned upright, the exhaust pipes will further spread to the left and right.
Another preferable feature of the present invention is that the exhaust pipes are gathered under the engine while the oil filter is disposed in front of the gathering of the exhaust pipes. Since there is a difference in exhaust pipe temperature across the gathering and the temperature of the exhaust pipes after the gathering is higher than that before that, placement of the oil cooler at a site open to the atmosphere located before the gathering where the exhaust pipes are lower in temperature, makes it possible to improve the performance of cooling the oil. Further, as to the oil filter, this configuration similarly makes the oil unlikely to be affected by heat from the exhaust pipes, producing a preferable result.
Still another preferable feature of the present invention is that the bodywork of the motorcycle including the engine sides is covered by the faring. Since, in such a motorcycle with a fairing, the left and right sides of the engine are enclosed by the fairing, the oil filter and oil cooler need to be arranged in front of the engine. Therefore, this configuration of the invention is particularly effective. Further, the oil cooler is arranged on the mounted side of the water pump on the engine with respect to the front to rear direction of the vehicle, the distance between the oil cooler and water pump can be reduced thus making it possible to minimize the length of the water hose. Accordingly, it is possible to prevent the cooling water from being warmed by heat from the engine and hence improve the cooling efficiency.